Sulfides dissolved in wastewater cause problems in wastewater lines, one of the most remarkable of which is bad odor. Dissolved sulfides, like hydrogen sulfide H2S, are generated when organic matter in the wastewater lines are degraded through anaerobic digestion by bacteria. The level of sulfides can however be controlled using suitable chemicals.
Previously, the level of sulfides has been indirectly estimated on the basis of atmospheric levels of H2S nearby the actual wastewater flow. The atmospheric levels have been used to control pumps that are arranged to feed odor control chemical to the wastewater line. This method is not as accurate as correlating feed rates to an actual dissolved sulfides level. Also physical grab samples have been taken to measure dissolved sulfides levels (e.g. by using a methylene blue test kit). Both these methods have involved a lot of measurement data and still automatic control has not been achieved, but manual control has been necessary. Also, the previous methods have not been real-time.
Thus, there exists a need for improved control methods and systems.